U.S. Pat. No. 6,493,575 B1 discloses a system for determining the orientation of a catheter. Radial marker bands surround the distal end of the catheter at predefined intervals. Furthermore, an asymmetric marker being wedge-shaped is attached proximal to the distal end of the catheter. For determining the orientation of the catheter a projection image of the radial marker bands, the asymmetric marker and the distal end of the catheter itself is needed.